How do you separate other metals, like copper, from pure silver, when melting it?Do they burn away w/ borax?

Question

I was melting a piece of jewelry, and some of the metal seemed not to be silver. How would I seperate?

Answer 1

Silver is separated from copper by a metallurgical process called electrorefining. Melt the silver-copper metal into an anode and electrolize it with a stainless steel cathode with a DC current source 40 to 50 Amps per square foot (about 2.5 volts) in a solution of copper–silver–nitric acid. Silver crystals will form on the cathode and the copper will dissolve into solution. Two different electrorefining techniques used industrially by silver produces are the Moebius (vertical) and Thum Balbach (horizontal) processes.

Additionally, here http://www.crscientific.com/article-silver.html someone has detailed their work to separate the Ag and Cu in Sterling silver. If you actually try to do this, please observe all of the safety warnings. Place a rings worth of sterling silver (92.5% Au and 7.5% Cu) in a 250 cc beaker filled with about 75 cc of concentrated nitric acid. Heat the solution in a properly ventilated hood (note: toxic nitrogen oxides will be released as reddish-brown fumes). The metal will dissolve and the solution color should become blue to green. Let solution cool. When the solution is cool, dilute it with distilled water to about 200 cc. Filter out any remaining solids. Three ways to get the silver out and leave the copper in solution are:
1.Electrorefine the silver (Ag) out,
2.Precipitate silver nitrate (AgNO3) crystals by evaporation
3.Precipitate silver chloride (AgCl) by adding salt (NaCl)

Answer 2

The tree is right on the money. I've never been able to understand people who want to subcategorize and pigeonhole everything. Maybe it's a form of OCD, I'm not sure. Even though it's clear that metal is just another branch of the old R&R tree, I still say it wouldn't be the worst thing in the world for metal to have it's own section on Answers. If only to give the whole "X is more brutal than Y and Z pees sitting down" crowd somewhere to wage their dull campaigns.

Answer 3

No. There is no easy way to separate metals like copper which have been alloyed with silver (usually to harden it) by just melting.

These alloys (like Sterling silver and coin metal) tend to melt at lower temperatures than pure Silver, but they do not separate with simple fluxes.

Methods usually used to purify the Silver would include strong acids and electrolysis.